Title: Tool for installing valve locks
Abstract: A hand tool that greatly expedites the installation of the valve locks that secure a valve spring retainer to the free end of a valve stem. The valve locks include an inwardly extending ridge that engages a circumferential groove that extends around an end portion of the valve stem. The valve lock is retained in this position by a tapered central bore of the valve spring retainer that produces an inward clamping force on the valve lock. The tool includes a plunger having a diameter equal to the diameter of the valve stem. The user positions the valve locks on the protruding cylindrical surface of the plunger, where they are held by magnetic attraction. The user pushes the end of the tool against the valve spring retainer, thereby compressing the valve spring so that the valve stem pushes the plunger into a close-fitting loader end cap until the valve locks are transferred to the valve stem and into engagement with the circumferential groove.
Patent Number: 6,892,430 Issued on 05/17/2005 to Levy, et al.
| Inventors:
|
Levy; Andrew L. (P.O. Box 5356, San Luis Obispo, CA 93403);
Wouters; Harry A. (424 Rose La., Paso Robles, CA 93446)
|
| Appl. No.:
|
289153 |
| Filed:
|
November 5, 2002 |
| Current U.S. Class: |
29/249; 29/214 |
| Intern'l Class: |
B23P 019/04 |
| Field of Search: |
29/2131,249,282,280,275,214,888,42,215
|
References Cited [Referenced By]
U.S. Patent Documents
| 5752308 | May., 1998 | Maley et al.
| |
| 5761785 | Jun., 1998 | Connolly.
| |
| 5842260 | Dec., 1998 | Todd, III et al.
| |
| 5915740 | Jun., 1999 | Weitner.
| |
| 5996201 | Dec., 1999 | Ringle.
| |
| 5996202 | Dec., 1999 | Bramante.
| |
| 6219896 | Apr., 2001 | Levy.
| |
| 6412158 | Jul., 2002 | Moore.
| |
| 6473965 | Nov., 2002 | Levy et al.
| |
Primary Examiner: Watson; Robert C.
Attorney, Agent or Firm: Lebens; Thomas F., Sinsheimer, Schiebelhut & Baggett
Parent Case Text
This application is a continuation of 09/733,749 filed Dec. 9, 2000 for TOOL
FOR INSTALLING VALVE LOCKS, now U.S. Pat. No. 6,473,965, which is a division of
09/394,483 filed Sep. 11, 1999, now U.S. Pat. No. 6,219,896, for TOOLS FOR INSTALLING
VALVE LOCKS, fully incorporated herein by this reference.
Claims
1. A hand-held tool for use in the field of automotive mechanics, comprising:
a hollow body containing a loader body and compression spring, and
a loader end cap affixed to said loader body; and a cylindrical bore running
axially through said loader body; and
a magnetized cylindrical plunger for use in engaging a valve lock slidably seated
within said cylindrical bore wherein said cylindrical bore is of a diameter slightly
larger than said plunger, said plunger protruding beyond the end of said loader
end cap.
2. The tool of claim 1, wherein said plunger is slidably forced inside of said
cylindrical bore when pressure is applied to the end of said plunger.
3. The tool of claim 1, wherein said plunger is magnetized by securing a magnet
to the end of said plunger.
4. The tool of claim 3, wherein said magnet is secured to said plunger by an adhesive.
5. The tool of claim 1, wherein said valve locks are attracted to said magnetized
cylindrical plunger by a magnetic field created by said magnetized cylindrical plunger.
6. A hand-held tool for use in the field of automotive mechanics, comprising;
a hollow body containing a loader body and compression spring; and
a loader end cap affixed to said loader body; and
a cylindrical bore running axially through said loader body; and
a cylindrical plunger for use in engaging a valve lock slidably seated within
said cylindrical bore wherein said cylindrical bore is of a diameter slightly larger
than said plunger, said plunger protruding beyond the end of said loader end cap,
said protruding end of plunger having viscous paste applied thereto.
7. The tool of claim 6, wherein said viscous paste is any of the group consisting
of grease and petroleum jelly.
8. The tool of claim 6, wherein said viscous paste is useful for securing said
valve lock to said plunger.
9. The tool of claim 6, wherein said plunger is slidably forced inside of said
cylindrical bore when pressure is applied to the end of said plunger.
10. The tool of claim 6, further comprising a spring internal to said plunger.
11. The tool of claim 6, further comprising a spring internal to said plunger.
12. A hand-held tool for use in the field of automotive mechanics, comprising:
a hollow body containing a loader body and compression spring; and
a loader end cap affixed to said loader body; and
a cylindrical bore running axially through said loader body; and
a plunger having an internal spring for use in engaging a valve lock slidably
seated within said cylindrical bore, wherein a viscous paste is applied to said
protruding end of plunger.
13. A hand-held tool for use in the field of automotive mechanics, comprising:
a hollow body containing a loader body and compression spring; and
a loader end cap affixed to said loader body; and
a cylindrical bore running axially through said loader body; and
a plunger having an internal spring for use in engaging a valve lock slidably
seated within said cylindrical bore, wherein said plunger is magnetized.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is in the field of automotive mechanics and specifically
relates to a tool for installing valve locks on a valve stem. The valve lock removably
secures a valve retainer to the valve stem. The tool typically would be used by
an automobile mechanic or by an engine reconditioner.
2. The Prior Art
During the compression and expansion cycles, the valves of a conventional
internal combustion engine are forced shut by the high pressure within the cylinder.
To implement the intake and exhaust cycles, the valves must be opened at appropriate
times, and this is usually accomplished by the use of a cam that pushes against
the end of the valve stem, thereby forcing the head of the valve into the combustion
chamber. To assure positive operation, a valve spring urges the valve to its closed
position, and the cam must overcome the urging of the valve spring to open the
valve. Typically, the valve spring is a compression spring. One end of the compression
spring bears against a stationary part of the engine, and the other end of the
spring bears against a valve spring retainer that is removably secured to the valve
stem by a valve lock. Were it not for the valve lock, the compressive force of
the valve spring would push the retainer off the end of the valve stem. The retainer
must be removably secured to the valve stem to permit assembly and dis-assembly
of the valve.
In theory, a nut and washer would suffice to secure the retainer to the valve
stem. However, after nearly a century of experience, a specialized type of valve
lock is almost universally used. The retainer has a tapered central bore that opens
toward the end of the valve stem. The valve stem has an end portion that includes
a circumferential groove. The valve lock is a tapered split collar that has an
inwardly facing ridge. The ridge engages the circumferential groove of the valve
stem and is held in engagement by the taper of the central tapered bore of the
retainer. The valve lock is thus jammed between the circumferential groove on the
valve stem and the tapered central bore of the retainer, which is urged toward
the end of the valve stem by the valve spring.
Although this way of securing the retainer to the valve stem is simple and
effective in use, it has proven to be very challenging for most mechanics to take
apart and reassemble, which must be done when the valves are ground or the engine
is reconditioned.
Part of the difficulty is that the retainer must be drawn back, away from the
end of the valve stem against the urging of the valve spring, to expose the valve
locks. In contemporary engines, the force exerted by the valve spring is in the
range of 60 to 90 pounds, and mere finger pressure generally is not adequate. Another
part of the difficulty is that the valve locks are rather small in comparison to
the valve stem and are difficult to manipulate. To make matters worse, the valve
spring and the retainer are frequently located in a poorly-illuminated and fairly
close-fitting recess, which makes the parts somewhat inaccessible.
Large console-type machines are commercially available, but they merely compress
the valve springs. They occupy valuable floor space in the shop, and have a high
initial cost. It appears that a need exists for a hand tool to facilitate the installing
of valve locks.
SUMMARY OF THE INVENTION
The present invention is a hand tool to facilitate the installation of a valve
lock into a circumferential groove on a valve stem.
In accordance with the present invention, the tool includes a loader end cap
having
an end that faces the valve spring retainer when the tool is in use and further
includes a central bore extending in the direction of the axis of the valve stem
when the tool is in use. A plunger extends through this bore and protrudes beyond
the end of the loader end cap. The plunger is biased toward the valve stem and
has the same diameter as the valve stem. The valve locks are placed by the user
on the protruding cylindrical surface of the plunger, and the axis of the plunger
is brought into alignment with the axis of the valve stem. The user then pushes
the tool against the valve spring retainer, gradually depressing the retainer by
compressing the valve spring, and the end of the valve stem makes contact with
the protruding end of the plunger. As the tool is pushed onto the valve stem, the
valve stem forces the plunger back into the loader end cap, and the valve locks
are pushed onto the valve stem by the loader end cap. The valve locks engage the
circumferential groove on the end portion of the valve stem, and as the tool is
withdrawn, the retainer advances toward the end of the valve stem also engaging
the valve locks and preventing them from coming out of the circumferential groove.
The tool of the present invention permits the valve locks to be installed in
a valve in approximately 15 seconds per valve, which is one-third to one-quarter
of the time previously required, depending on the mechanic. The hand tool of the
present invention occupies no floor space in the shop, and costs only about one-tenth
of the cost of the large console-type machines currently on the market.
The operation of the tool as well as its construction will be described in detail
in the following paragraphs with the help of the accompanying drawings. The drawings
show a preferred embodiment of the invention, but should not be regarded as limiting
the scope of the invention.
The novel features which are believed to be characteristic of the invention,
both as to organization and method of operation, together with further objects
and advantages thereof, will be better understood from the following description
considered in connection with the accompanying drawings in which several preferred
embodiments of the invention are illustrated by way of example. It is to be expressly
understood, however, that the drawings are for the purpose of illustration and
description only and are not intended as a definition of the limits of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view partly in cross section showing a type of
valve assembly used in the prior art;
FIG. 2 is a side elevational exploded view partly in cross section showing the
removal of the valve locks from the valve stem following compression of the valve
spring in the prior art assembly of FIG. 1;
FIG. 3 is a front perspective view of a valve lock of a type used in the prior
art and shown enlarged relative to FIGS. 1 and 2;
FIG. 4 is a perspective view showing a preferred embodiment of the hand tool
of the present invention;
FIG. 5 is a fractional side elevational view partly in cross section showing
a valve assembly and the tool of the present invention after the tool has been
prepared for use but before the tool has been applied to the valve assembly;
FIG. 6 is a fractional side elevational view partly in cross section showing
the tool and the valve assembly at the instant when the end of the valve stem first
makes contact with the end of the plunger of the tool;
FIG. 7 is a fractional side elevational view partly in cross section showing
the tool and the valve assembly after the tool has been used to push back the valve
retainer to a greater extent than in FIG. 6, and in which the valve locks have
been pushed onto the valve stem;
FIG. 8 is a fractional side elevational view partly in cross section showing
the tool and the valve assembly after the valve retainer has been pushed back to
a greater extent than in FIG. 7, and in which the valve locks have become seated
in the circumferential groove of the valve stem;
FIG. 9 is a fractional side elevational view partly in cross section showing
the tool and the valve assembly as the tool is being withdrawn from the valve assembly;
FIG. 10 is a fractional side elevational view partly in cross section showing
the tool and the valve assembly with the tool further withdrawn than in FIG. 9
and in which the valve spring retainer engages the valve locks;
FIG. 11 is a fractional side elevational view partly in cross section showing
the tool and the valve assembly after the tool has been withdrawn from the valve
assembly; and,
FIG. 12 is a fractional side elevational view partly in cross section and enlarged,
showing a preferred embodiment of the tool in greater detail.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a typical valve assembly of a type used in a contemporary internal
combustion engine. The head
12 of the valve forms a movable portion of the
wall
14 of the combustion chamber
16. FIG. 1 shows the valve in its
closed position, and the valve opens when it is moved in the direction indicated
by the arrow. This motion is produced by a cam (not shown) that bears against the
end
18 of the valve stem
20.
The head
12 of the valve is biased into its closed position by the valve
spring
22, which is a compression spring. One end
24 of the valve
spring bears against a fixed portion
26 of the engine. The other end
28
pushes against the valve spring retainer
30 which is attached to the valve
stem
20.
The valve spring retainer
30 is removably attached to the valve stem
20
by two valve locks
32 and
34, which are shown diagrammatically in
FIG. 2; a single valve lock is shown greatly enlarged and in full detail in FIG.
3. As best seen in FIG. 3, each valve lock includes a cylindrical inwardly-facing
surface
36, a tapered outwardly-facing surface
38, and a ridge
40
that protrudes inwardly from the surface
36.
The valve stem
20 includes an end portion
42 into which a circumferential
groove
44 has been formed. The valve spring retainer
30 includes
a tapered central bore
46.
FIG. 1 shows the valve stem
20, the valve locks
32 and
34
and the valve spring retainer
30 in their normal assembled configuration.
In FIG. 2 the valve spring retainer
30 is shown drawn back from the end
18 of the valve stem to permit removal of the valve locks
32 and
34 and subsequent dis-assembly of the valve spring retainer
30 and
the valve spring
22.
From FIGS. 1,
2 and
3 it is seen that the ridge
40 of each
valve lock engages the circumferential groove
44 of the valve stem
20,
and the valve locks
32 and
34 are forced radially inward by the tapered
central bore
46 of the valve spring retainer
30 which bears against
the tapered outwardly-facing surfaces
38 of the valve locks, the valve spring
retainer
30 being pushed toward the end
18 of the valve stem by the
valve spring
22.
As mentioned above, the assembly of FIG. 1 is typically located in a recessed
portion of the engine and therefore is not easily accessable to most tools. Typically
the valve spring is quite stiff and cannot be compressed sufficiently by mere finger
pressure to permit the valve locks to be disengaged. Also, typically the valve
locks are relatively small, on the order of 6 millimeters in length and 8 millimeters
in diameter. The combined result of these factors is to make it difficult to disassemble
and to re-assemble the valve assembly.
In an attempt to solve this acute problem, large console-type machines have been
developed to support the cylinder head while simultaneously pressing on the valve
spring retainers to permit the valve locks to be exposed. These machines typically
occupy six square feet of floor space, and they provide no help in handling the
valve locks.
In contrast with such large console-type machines, the present invention is a
lightweight hand-held tool that is adapted not only to compress the valve spring,
but also to set the valve locks into engagement with the circumferential groove
of the valve stem. FIG. 4 shows an external view of the tool of the present invention,
and FIGS. 5-11 show successive stages in its operation.
FIG. 4 is a perspective view showing the exterior of the hand tool of the present
invention. The tool includes a handle
48 affixed to a hollow body
50
having an end
52 and a central axis
54. A knob
56 is used
for adjusting the tool and in replacing certain internal parts to adapt the tool
for use with various engines. The knob
56 is attached to a threaded bolt
(not shown in FIG. 4) that extends through the slot
58.
FIG. 5 shows the components of the valve assembly discussed above as well as
certain essential elements of the tool. These include the hollow body
50,
a loader end cap
60 affixed to the hollow body
50, having a central
bore
62, and having an end
64. A plunger
66 having a head
70 also includes a cylindrical body
68 that extends through the central
bore
62 of the loader end cap
60 and fits therein in a loose sliding
fit. When the head
70 of the plunger is in contact with the loader end cap,
as in FIGS. 5 and 6, an end portion
72 of the plunger extends beyond the
end
64 of the loader end cap. The plunger terminates in an end
74.
The head
70 of the plunger
66 is biased toward the loader end cap
60 by the plunger biasing means
76, which is a compression spring.
The spring
76 is contained within a loader body
78.
FIG. 5 shows the condition of the valve assembly and of the tool immediately
prior to use. The valve spring
22 has been set in place over the valve stem
20, and the valve spring retainer
30 is positioned at the end of
the valve spring
22. The user has placed the valve locks
32 and
34
on the cylindrical surface of the protruding end portion
72 of the plunger
66. The means used to prevent the valve locks from filling off the protruding
end of the plunger will be described in greater detail below.
As indicated in FIG. 5, the user has manipulated the tool to bring the central
axis
54 into coincidence with the central axis
80 of the valve stem.
Next, as shown in FIG. 6, the user pushes the tool against the valve spring
retainer
30, compressing the valve spring
22, permitting the tool
to advance toward the valve stem sufficiently that the end
18 of the valve
stem makes contact with and coincides with the end
74 of the plunger
66.
As the user continues to advance the tool, the end
18 of the valve stem
pushes the plunger
66 into the loader end cap
60 against the urging
of the spring
76, as shown in FIG.
7. The end
64 of the loader
end cap
60 pushes the valve locks
32 and
34 along the end
portion
72 of the plunger and thereafter onto the valve stem
20.
As the user continues to advance the tool, as shown in FIG. 8, the valve locks
32 and
34 engage the circumferential groove
44 of the valve stem.
Thereafter, the user draws the tool away from the valve stem as indicated
in FIG. 9 until, as shown in FIG. 10, the advancing valve spring retainer
30
engages the valve locks
32 and
34. The tapered central bore
46
of the valve spring retainer
30 presses against the valve locks, pushing
them radially inward into the circumferential groove
44 and preventing further
movement of the valve spring retainer.
Finally, as shown in FIG. 11, the tool is removed from the valve spring
retainer and the task of seating the valve locks
32 and
34 has been completed.
From the above description it can be recognized that there exists a need for
some means for keeping the valve locks
32 and
34 in contact with
the end portion
72 of the plunger in the positions shown in FIGS. 5 and
6, and in contact with the end portion
42 of the valve stem, as in FIG.
7. If one or both of the valve locks were to fall off the protruding end
portion
72 of the plunger while the tool is being brought into position,
the valve lock might fall into the engine or onto the floor, and retrieving it
could be time consuming.
In accordance with the present invention, several ways of keeping the valve locks
in contact with the plunger have been devised, and they will now be discussed.
FIG. 12 is an enlarged fraction of FIG.
6. In FIG. 12, the central axis
80 of the valve stem is shown oriented vertically because in practice the
valve stem is typically oriented approximately vertically. This permits the user
of the tool to use his weight in pushing down on the tool to compress the valve
spring. In the preferred embodiment shown in FIG. 12, the plunger
82 is
composed of a non-magnetic material such as non-magnetic stainless steel, aluminum,
brass, or nylon. The plunger
82 includes a hollow bore that extends almost
to the protruding end of the plunger. A powerful cylindrical-shaped permanent magnet
86 is secured to the end of the hollow bore
84 by an adhesive. The
north and south poles of the magnet are aligned with the central axis of the bore
84. The loader end cap
60 is composed of a ferromagnetic material,
as are the valve locks and the valve stem. In the preferred embodiment, the permanent
magnet
86 is composed of a rare earth alloy, which results in an extremely
strong magnetic field. The magnetic field attracts the valve locks to the surface
of the plunger thereby preventing the valve locks from falling away as the tool
is being brought into position.
As indicated in FIGS. 6,
7 and
8, as the user pushes the tool against
the valve spring retainer
30, the latter yields and is depressed with respect
to the end
18 of the valve stem. Thus, the valve stem pushes the plunger
upward, as seen in FIG. 12, so that the permanent magnet
86 is carried into
the ferromagnetic loader end cap
60. Because of its ferromagnetism, the
loader end cap provides a preferred path for the magnetic lines of flux, which
disengage from the valve locks thereby releasing them.
In a first alternative embodiment, the plunger is composed of a ferromagnetic
material and is permanently magnetized. The magnetism retains the valve locks against
the protruding end of the plunger. In addition, the permanently magnetized plunger
magnetizes the end portion
42 of the valve stem, and when the plunger is
retracted into the loader end cap, the valve locks are retained in contact with
the valve stem by the magnetism.
In a second alternative embodiment, a viscous paste is applied to the protruding
end of the plunger, and if necessary to the end portion
42 of the valve
stem. The viscous paste may be a grease or a petroleum jelly.
As suggested by FIG. 12, at the instant the ridges
40 of the valve locks
seat in the circumferential groove, the valve spring retainer
30 must be
sufficiently far down along the valve stem to permit the valve locks to move to
their final position. Thus, the distance between the end
64 of the loader
end cap
60 and the end
52 of the hollow body must exceed some critical
dimension. This critical dimension varies from one engine to the next, because
the valve spring retainers and valve stems have different shapes from one engine
to the next. In accordance with the present invention, the distance between the
end
52 of the hollow body of the tool and the end
64 of the loader
end cap is set for a particular engine by inserting a loader body
88 of
appropriate length into the hollow body
50 of the tool. For a particular
engine, the user must select the appropriate loader body
88 and insert it
into the hollow body
50 of the tool along with a loader end cap
60
that has a central bore
62 equal in diameter to the diameter of the valve
stem to be worked on.
Thus, there has been described a preferred embodiment and alternative embodiments
of the tool of the present invention. The tool greatly expedites the installation
of the valve locks, and is considerably less expensive than equipment previously
used for installing the valve locks.
The foregoing detailed description is illustrative of several embodiments of
the invention, and it is to be understood that additional embodiments thereof will
be obvious to those skilled in the art. The embodiments described herein together
with those additional embodiments are considered to be within the scope of the invention.
*
